Reciprocating and Rotating Components

In Simple Terms

This rule specifies what materials can be used for moving parts in the engine like pistons and rotating shafts. Most of these components must be made from traditional materials like iron-based alloys or ceramics, not advanced composite materials. The exception is for clutch discs and seals, which have different material rules.

• Reciprocating and rotating engine components are restricted to iron-based alloys, ceramics, or traditional materials
• Advanced composite materials (graphitic matrix, metal matrix composites) are generally prohibited for these parts
• Clutch discs and seals are exempt from these restrictions and can use other approved materials
• Rolling elements must be made from iron-based alloys or ceramics, and timing gears must use iron-based alloys